Security readout for executives and security teams
Plain-English summary
This flaw can let someone log in to affected Nextcloud or ownCloud accounts without valid credentials, but only when the optional SMB authentication backend was manually enabled. Organizations that never configured SMB authentication are not affected according to the source description.
Executive priority
Prioritize quickly if Nextcloud or ownCloud uses SMB authentication, because the impact is account access without valid credentials. If SMB authentication is not configured, document non-exposure and treat as routine legacy version hygiene.
Technical view
The SMB authentication backend treated a successful SMB connection as successful user authentication. SMB servers allowing anonymous authentication could therefore cause the backend to accept unauthenticated users. Affected versions are Nextcloud Server before 9.0.54 and 10.0.1, and ownCloud Server before 9.1.2, 9.0.6, and 8.2.9.
Likely exposure
Exposure is limited to Nextcloud or ownCloud deployments using the optional SMB authentication component. The component is disabled by default and requires manual configuration, so many installations should be unaffected.
Exploitation context
The bundle does not show CISA KEV listing or active exploitation evidence. Public references include vendor advisories, commits, HackerOne reporting, and a Rhino Security Labs post, but this analysis should not infer current exploitation from those alone.
Researcher notes
This is CWE-303, incorrect authentication. The key condition is interaction between the optional SMB backend and SMB servers permitting anonymous authentication. Evidence is strongest for affected versions, configuration dependency, and fixed release thresholds; exploit prevalence and broader product impact are not established here.
Mitigation direction
- Upgrade Nextcloud to 9.0.54, 10.0.1, or later supported versions.
- Upgrade ownCloud to 8.2.9, 9.0.6, 9.1.2, or later supported versions.
- Disable the SMB authentication backend if it is not required.
- Review SMB servers used for authentication for anonymous access settings.
- Check current vendor guidance for any environment-specific remediation.
Validation and detection
- Identify all Nextcloud and ownCloud server versions in use.
- Check configuration files for the SMB authentication backend.
- Confirm SMB authentication is disabled where not intentionally used.
- Verify patched versions are deployed on systems using SMB authentication.
- Confirm authentication depends on valid credentials, not only SMB connection success.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-303: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCredential and access behavior lookup
The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2016-9463 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/nextcloud/apps/commit/b85ace6840b8a6704641086bc3b8eb8e81cb2274CVE reference · x_refsource_MISC
- https://github.com/owncloud/apps/commit/16cbccfc946c8711721fa684d78135ca1fb64791CVE reference · x_refsource_MISC
- https://rhinosecuritylabs.com/2016/10/operation-ownedcloud-exploitation-post-exploitation-persistence/CVE reference · x_refsource_MISC
- https://github.com/owncloud/apps/commit/5d47e7b52646cf79edadd78ce10c754290cbb732CVE reference · x_refsource_MISC
- https://github.com/owncloud/apps/commit/a0e07b7ddd5a5fd850a6e07f8457d05b76a300b3CVE reference · x_refsource_MISC
- https://hackerone.com/reports/148151CVE reference · x_refsource_MISC
- https://github.com/nextcloud/apps/commit/decb91fd31f4ffab191cbf09ce4e5c55c67a4087CVE reference · x_refsource_MISC
- https://owncloud.org/security/advisory/?id=oc-sa-2016-017CVE reference · x_refsource_MISC
- https://nextcloud.com/security/advisory/?id=nc-sa-2016-006CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Incorrect Implementation of Authentication Algorithm
Incorrect Implementation of Authentication Algorithm represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.